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Vertebrae are stacked in a
Vertebral column: which runs the length of the back.
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The vertebra are named by
region, then number, from superior to inferior.
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The most superior seven vertebrae called
Clervical (neck). The region is designated by a letter "C" and number, C1-C7
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What comes after the cervical region?
12 Thoracic (chest) vertebrae. Each of them have a matching rib; there are 12 matching ribs. T1-T12
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The last 5 with joints between them
Lumbar (loin) vertebrae, L1-L5.
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L5 usually forms a joint with the
first sacral (holy) vertebrae (S1). In most people, there are five fused sacral vertebrae. That is, S1 through S5 are joined in an immobile, locked state.
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Several small coccygeal vertebrae fuse to form the
coccyx (tailbone), the end of the vertebral.
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The largest part of the vertebra is the
body.
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A joint between two adjacent bodies is filled with a disk of fibrocartilage that has a soft center, like a jelly donut. This is called the
Intervertebral disc
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Two _________ ________ extend laterally; a ______ connects each of these to the body.
transverse processes; pedicle
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Along the midline, there is a _______ _______ which protrudes posteriorly. This is joined to the transverse processes by _______.
spinous process; laminae
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Taken together, the medial surfaces of the body, processes, pedicles and laminae form a large hole called the ______ _______ that allows passage of the spinal cord.
Vertebral foramen
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The first cervical (C1) and second cervical (C2) vertebrae are highly specialized. These need to allow for 80 degree rotation while
supporting the weight of the head.
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Atlas = C1
The joint between the occipital bone of skull and the atlas is called the atlanto-occipital joint. This joint allows us to nod.
-No body, minimal spinous process
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Axis = C2
- small body
- body contains tooth-like "peg" (dens) which projects superiorly into vertebral foramen of atlas
- not shown: transverse ligament of C1 which holds dens in place but allows for rotation
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Cervical vertebrae 3-7 are more
typical
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One unique feature of cervical vertebrae is that the posteriorly-projecting spinous process (the one on the midline) is
bifid - (two-pronged) spinous process. It has a "forked tongue".
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C7 is called
Vertebra prominens; because it can easily be palpated (felt with your fingers) along the back of your neck.
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Ribs articulate at two points
Transverse process of vertbra ----> tubercle of rib
Body of vertebrae ----> head of rib
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Inferior articular fact of more superior vertebra forms
moveable joint with superior articular facet of more inferior vertebra
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Lumbar vertebrae designed to carry a
large amount of weight.
-Therefore have thick, strong body.
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In conventional lateral spine x-rays, lumbar vertebrae resemble a
"scotty dog"
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Sacrum is made up of
5 fused vertebrae (S1-S5)
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Coccyx is made up of
3-4 fused vertebrae (number varies)
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Transitional vertebrae are a relatively common anatomical variation
- In 10% of humans, there is an internertebral disk & joint between S1-S2 (lumbarization of S1)
- In 14% of humans, there is a fusion of L5 and S1 (sacralization of L5)
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